Squeeze film dampers are commonly used to avoid high vibrations and instability encountered in high performance rocket engines and aviation turbomachinery. Squeeze film dampers are annular supports of major bearings and respond to the lateral bearing loads such that rotor motion is damped, especially at rotor resonances (i.e. critical speeds). In a typical squeeze film damper a viscous fluid, e.g. oil, is trapped in an annular groove which houses a bearing support ring. The fluid is sealed with o-rings between the groove walls and the bearing support ring. The support ring assumes different eccentric positions relative to the groove by following the lateral motions of the rotor bearing. The damping fluid is thus rushed and squeezed circumferentially inside the annular groove which causes a damping effect. A supply source replenishes the damping fluid to keep the groove filled when leaks occur through the o-rings on the groove walls. The groove contains occasionally a circumferential wave spring to better center the bearing and to provide more stiffness in supporting the bearings. Too much stiffness, however, diminishes the damping effect and too little stiffness permits excessive rotor motion and rubbing.
Accordingly, what is proposed is a damping seal that restricts leakage like a labyrinth seal and, also, extends the stable rotor speed range to more than twice the first critical speed.